package main

import "fmt"

func main() {
	fmt.Println(getMin(1680, 640))
}

func getMin(c int, k int) int {
	var temp int = 0
	if k > c {
		temp = c
		c = k
		k = temp
	}
	temp = c
	c = k
	k = temp % k
	if k == 0 {
		return c
	} else {
		return getMin(c, k)
	}
}
